INTRODUCTION AND BACKGROUND. The Research Career Award to Professor Maurice Green for the past 46 years is greatly appreciated by the University. The Award has allowed a distinguished faculty member of the Saint Louis University Medical School to develop an outstanding research program and to establish and strengthen the Institute for Molecular Virology, a center for research and training in cancer biology, tumor virology, and AIDS research. Because of his Research Career Award, the greater part of Dr. Green?s administrative duties in the operation of the Institute are delegated to a Business Administrator and to an Office Manager. Dr. Green's major activity continues to be research and teaching. In addition to conducting and directing his research program, he lectures on tumor virology and oncology to medical students and participates in the Core interdepartmental graduate training program on Cell and Molecular Biology. Dr. Green serves on the Executive Faculty Committee, on the Dean's Chairmen's Committee and on the Dean?s Research Planning Committee of the School of Medicine as well as on the Internal Advisory Board of the Cancer Center. The laboratory of Dr. Maurice Green has made many seminal contributions which have helped to develop the human adenoviruses (Ad) as prototype systems to study virus replication, cell transformation, and the molecular biology of the human cell. Because of these early studies, Ads have become powerful and important model systems that are used worldwide. Dr. Green continues to have an innovative research program which focuses on the oncoproteins encoded by Ad early region 1A (E1A). E1A functions are essential for efficient adenovirus replication in human cells. Towards this end, E1A has evolved protein sequences that interact with pivotal cellular transcription regulatory proteins and cellular gene promoters to control cell cycle progression, cell differentiation, and chromatin remodeling. E1A proteins encode multiple independent domains with diverse biochemical and biological functions including transcriptionalactivation, transcriptional-repression, induction of cellular DNA synthesis, cell immortalization, cell transformation as well as, paradoxically, the inhibition of metastasis and cell differentiation. We have a limited understanding of the specific molecular mechanisms and the precise role of cellular regulatory factors in these processes. The systematic study of E1A functional activities provides important opportunities to explore important and complex questions in cell growth regulation, oncogenesis, and virus control.